Algorithms & Data Structures

Algomation  A didactic, animated, exposition of algorithms.

Algorithm Visualizer  Dozens of animated algorithms (with code), and you can also create your own.

Algorithms Visualization  A dense article on Algorithms Visualization.

BigO Cheat Sheet  BigO complexities of common algorithms used in Computer Science.

Geeks for Geeks  Lots and lots of well explained and implemented algorithms.

VisuAlgo  Visualising data structures and algorithms through animation.
Online courses
Free and high quality online courses

Algorithms, Part II  Part II focuses on graph and stringprocessing algorithms.

Khan Academy Algorithms  Algorithm course ministred by Tomas Cormen and Devin Balkcom.

MIT  6046j  Similar to the previous one, but with different algorithms.

MIT  600sc  An easy and well explained introduction to algorithms.

Udacity Intro to Algorithms  Pythonbased Algorithms course.
Books

Data Structures Using C  The basic concepts and usages of data structures.

Elementary Algorithms  An awesome book about algorithms and data structures.

Grokking Algorithms  An illustrated book on algorithms with practical examples.

Swift Algorithms & Data Structures  A practical guide to concepts, theory and code.

The Algorithm Design Manual  Easy to read and full of real world examples.